Lock-stitch sewing-machine.



W. WILSON. LOCK STITCH SEWING MACHI IE. ArruqATlon FILED JULY i0. 19 3.

1,216,035. v Patentpd Feb.13,1917.

STATESPATENT OFFICE.

WILLIAM WILSON, or nosron, nnssncnusn'rrs, ASSIGITQR TO CAMP ELL BOSWORTH IACBINEBY COMPANY, orron'rnnnn, mama. A conromi'rmn or MAINE.

To all iokom it may concern:

Be it known that I, WILLIAM WILSON, a citizen of the UnitedStates, residing at Boston, in the county of Suffolk 51nd State of Massachusetts, have invented certain new and useful I mpmvements in Lock-Stitch Sewing-Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to lock stitchsewing machines, and more particularly to lock stitch sewing machines in which the loop of needle thread is cast about a statiOlllitl'y bobbin case byimeans of a rotary hoo provide the sewing machine with means for ositively freeing the hook of the thread.

.he present invention, in one of its more limited aspects, relates to the combination ofa rotary hook for casting a loop of=thread around the ,bobbin case having a thread-receiving groove with an undercut recess in its side -in which the thread is held by its tenand Fig. 4 is a fragmentary section taken in the same section plane as Fig. 2 showing the undercutportion of'th'e hook without the thread.

In the illustrated embodiment oi the invention. a loop of thread is drawn down by a' verticallyjreciprocating barbed needle and is-cast' about the bobbin case 1 by means .of

arotary hook; indicatedgenerally by reference numeral 2, which rotates in a -plane inclined at about 60 degrees to the directionof reciprocation of the needle. 'The hook comprises'an annular. body porgtion 3 and an inwardly directed thread-engaging beak 4 which enters the loop of threaddrawn down by the needle and takes it from the barb ofthe needle. The annular body portion-3 of the hook has at its lower end 'an'inwardly projecting flange 5 which is engaged in an annular race-way formed between the body of the hook supporting frame 6'and a plate 7 secured'to'the'top of the supporting frame.

The objec f the present invention is-to LOCK-STITCH snwme-macm NE;

- Specification of Letters Patent. Patented Feb 13, 191 7, Application filed July 10; 1913. Serial No 778,326. I l

The hook rra'lces three revolutions to each reciprocatior. of the needle and is continuously rotatec in timed relation therewith by means of a b svel gear wheel 10 which meshes with bevel gear teeth 11 cut in the periphery of the annulir'body The barbed needle (not shown) passes upwardly through the passage 12 inthe hook supporting frame 6 and plate 7, through the annular body of the hook and through the cut-away portion 13. of the bobbin case, and draws down through the throat plate of the machine-a loop of thread which is entered by the beak 4. The loop of needle thread taken from the needle by tho beak 4 slips into the thread receiving gnove 8 of tlie'hook whichacts to spread the loop of needle thread and carry itaboub thebobbincase-l. The hook supporting f1 arms 6 is'a frame substantially U-shapedin outline having .two le s 15 and 16 inthe end, of which are-forme c'o-aXiaI -bearings'l7 and 18' by means of which the hook-supporting frame 6 is hingedtothe machine. Tl e hook support 6 is given a limited oscill: tion about the bearings '17.a1id

18 once for or cry reciprocation of the needle" so that the baak 4 will pass to the left, as

.viewed in Figs. 1': and 2, of the needle and" thus clear the needle during. the two idle rotations of ihe hook. The gear wheel 10. is mounted to rotate on tlie shaft 20, which is rigidly mounted in the supporting frame 6, and held in place by means" or the nut 21:

At the end oi the hub 220i the gear wheel 10 is formed a universal joint,23. through which power is transmitted from a' gear.

wheel 24 mounted to rotate u on a shaft25';

heibobbin case fixed to the in: chine-frame.

1 is discoidal in outlineahd is. rotatably mounted within theannular body ,3 of the hook upon-an annular plateBO which is rigidly secure 1 to .tii'eto 10f the hook body- 3 and which Ijes 111 a p ane normal to the axis of rotatn inof the hook and' 'the inner. periphery of,which is received-in a race-way 2100 p 31 cut around the periphery of the bobbin" case 1. The l)( bbin casehas inits upper end face a CIlP Shll ped bobbin-receiving recess 32 inwhich is a central post 33 upon which is rotatably inouziteda bobbin 34. The bobbin 34 is reniovably held in place'iby" means of a spring-pressed latch 35. l'rhe b0bbill case 1 is pr'evehted f1 rotatingjiwith the-supporting book 2 by means of detent pins 40 and 41" which eng mge circular detent-rec eiving' "on a cast-off pro ection extends in a direct on across the expanded by -leg of the loop extends from -the bobbin case from and 47 are provided at their lower ends with cum rolls which run in a cam move nd act to advance and withdraw t 1e detent pins 40 and 41 in timed relation with therotation that the loop of thread may be permitted to pass over the of the bobbin case. The detent pins 40 and 41 are provided'with thread guards and 71 to prevent the thread from catching on them. The above described parts have substantially the same construction and mode' of operation as those illustrated and described in the co-pending application of LaurenceE. Topham, Ser. No. 754 214. filed March 14', 1913, to which reference is had by ermissionl The mechanism herein descri d is a part of the lock-stitch wax- -thread harness sewing machine, known to the trade as the Campbell Cycloncstitcher.

The thread-receiving groove 8 of the hook plane of rotation of the hook, or in other words, in a direction generally lengthwise'of the bobbin case 1. The loop of needle thread is bobbin case so that the lower leg of the loop extends from the groove just below the lower end face of the bobbin case and the upper the groove just above the upper end face of the bobbin case.

he groove 8 is longitudinallyconvex. as shown in Fig. 3, at its lower end extending at approximately right angles to the plane of rotation of the hook and at its upper end terminating in.a. portionHO which is but slightly inclined to the plane of the hook. The upper-or inclined portion 80 of the -thread-receiving groove has in its inner wall an undercut recess-S1 in which the thread is drawn and is securely held. by its own tension as the hook carries the loop around the bobbin case. The thread-is positively lifted out of the-mulercut portion 82 of the bobbin case. 82 is a riser or cam This cast-off projectiondlametrically across beginning at; a point 83 graduallybeyond this point (in the direction of the movement of the thread around the bobbin case)v and again merging with the end face. of the bobbin case at a. point 84.

he operation of the machine is'as follows:-

The inwardly rected beak 4 takes-the loop, of thread from the neei'llc'barb. As the hook begins to carry the loop of thread around the bobbin case, thethread slips into the groove 8 which expands or spreads the,

the'loop to be pulled upper face plate or needle.

this groove lengthwiseof the.

of the groove by means of the edge of theuppcr end face- 'dcscribcd in the ncci llc, risingother in proximity to 7 thread substantially normal to the plane of loop lengthwise of the bobbin .case. As the thread-receiving groove 8 gets to the side, of the bobbin case plate of the mac line, the tension of the thread draws it firmly into the undfl'rcut recessSl, so that there is no ten'denc .for the side wisei pull of the thread, when 1; parts op osite the needle or throat are in the positions shown in Fig. 1, tu'bause thread-receiving groove 8. nfact,'the tighter the thread, the. more'firmly it is held in the undercut recess 81. The thread is thus securely held bv the hook un has performed its function in drawin out the loop to its greatest distention an our ryin it across the side of the bobbin case whici is diametrically opposite the throat After the loop has passed greatest distention (approxiit must be freed drawn in the In order to free its position-of mately shown'ln Fig. 1) from the hook so as to be take-up-of the machine. the hook of the thread at the cast-01f projection 82 is placed where it will operate to lift the thread out of the thread-receivin groove 8 shortly after the loop has passer tention. As shown in Fig. larly, the. thread which lies portion 83 of the thread-rece1ving groove mok is lifted or pushed in a direc 'on approximatel'v normal to the plane of rotation of th hook by means of the east-off p rojcction 2. As soon as the thread has been lifted by the cast-otf projection 82 out of the undercut inclined portion 83 of the groove, it can be readily pulled from the groove by the takc-up. The undercut recess 81 and the cast-oh" projection 82 cooperate with-each other to positively control the thread during the opcratiou of 3 more pa rticuor jum 'out of thethe b de the proper time its position ofgreatest disin the inclined bobbln case, for, as above pointed out, the

thread is snugly and securely held by its own tension in the undercut recess 81 until it is lifted from it by the cast-off projection 82. The cashilf projection 82 operates to free the book of the thread'at the same point during each cycle of thc stitch forming operations, so that uniformity iutlie stitches is secured.

While the preferred invention has been embodiment it is to be understood that the present invention is not limited to the illustrated embodiment, but may be embodied in constructions of sewing machines within the scope of the invention asset forth in the following claims.

I claim 1. A lock stitch in combination, a bobbin case, a rotary hoo for casting a loop of needle thread aboutthe bobbin case, and

connection with its preferredmeans engaging the'th read the hook and moving the 10s castingtheloop around the a rotation of the hook for lifting the thread out of the hook aftei" the loop has passed its position of n axiiniun distention in traveling aboutthe bobbin ease. 2. A lock stitch sewing 1n cointmiation, a bobbin case, a rotary hook hbok for lifting tl' c'thread out of the hook after the loop has passed its position of maximum distention in trzu'eling'about the bobbin case. .i

3. A lock stitch sewing machmehavmg,

in combimition, a stationary bobbin case, 'a

rotary hook for casting a loop of needle thread about the bobbin case, said bobbin case having a cast-oil projection for lifting the thread outof the hookafter the loop has passed its position ofimaximul'n distention in traveling about the bobbin case. i

4. A lock stitch sewing machine having in emnbination, a bobbin case, arotary hook for casting a loop of thread about the bobbin case' bavinga thread-receiving groove with an umlercut recess in one of its sidesin which the thread is held as the loop is carried around thebobbin case by the hook, and means for lifting the thread out of the un-' dercut recess after the loop has passed its position of nn xirnum distention in traveling about the bobbin case.

5. A look stitch sewing machinehaving, in combination, a stationary bobbin case, a rotary hook for casting a loop of needle thread about the bobbin case having {a threada'eceiving groove with an iuulercut in one of its sides in which the thread is held as the loop is carried around the bobstitch sewing machine having,

, in combination, a.stationary .bobbin case, a.

rotary hook for casting a loop of needle thread about the bobbin case havlng a machine having,

thread-receiving grooe terminating at one,

- thread out of the 11nd root end in a portion inclir ed to the plane of [0'1 tation of the hook, sad bobbin case having a cast-0E projectionfar moving the three substantially normal 10 the plane of rotation of the hook to lifl it out ofthe inclined portion of the groove after. the loop has passed its position of maximum distention in travelin about the bobbin case.

7. Aloc stitch sewing machine having, an

in combination, a 'stationary bobbin case, a rotary hook for sprea ling a loop of needle threadand casting it about the bobbin case having athread-recei 'ing groove extending in a dlrecti'on across the plane of rotation of the hook and termim ting at one end in a portion inclined to th: plane of rotation of the hook,said inclined portion having an undercut recess in uhich the thizead is held by its own tension as the loop is carried around the bobbin else, said' bobbin case having a cast-o'fi promotion for lifting the inclined portion of the groove.

8. A, lock stitch sewing machine having, in combination, a staxionary dlscoidal bobbin c ase, a-rotary hook having an annular body surrounding and supportin the bobbin case and having a threat -receiving groove for spreading loop of needle thread lengthwise of the bo'ib in case and castingv 'it about the bobbin ca ;e,.said groove'extending in a direction generally lengthwise of the bobbin case and tarminating at one end in a portion inclined to the plane of rot-a tion of the hook, said inclined portion hav ing an undercut recess in one of the sides oi the groove in which the thread ,is held by its own tension as the 191 p is carried about the bobbin case by the "h ook, said bobbin case having a cast-off projection 'for engaging the thread and lifting it outof the "undercut inclined'portion of th a groove after the loop has passedoits positio i of maximum distention in traveling about the bobbin case.

7 WlLLIAM WILSON.

Witnesses: r a

. CI-{ESTER E. R( GERS,

- RUTH E. WARI. 

